Moving magnetic storage devices, especially disk drives, are fast becoming the memory device of choice. This is due to their expanded nonvolatile memory storage capability together with a relatively low cost. Accurate retrieval of the stored information from these devices becomes critical, requiring the transducer to be positioned as close to the media as possible. Optimally, the transducer should touch the media.
Disk files are information storage devices which use at least one rotatable disk-with concentric data tracks containing data information. A combination transducer-slider-suspension assembly includes a transducer for reading the data from or writing the data to the various tracks, a slider for holding the transducer adjacent to the track generally in a flying mode above the media, and a suspension for resiliently holding the slider and the transducer over the tracks. A positioning actuator connects to the combination to move the transducer to the desired track and maintains the transducer over the track center line during a read or a write operation. The transducer is attached to the air bearing slider which supports the transducer close to the track by a cushion of air that is generated by the rotating disk. However, the transducer may be placed in contact with the disk. The suspension provides a high spring stiffness and dimensional stability between the slider and the actuator arm. The suspension is required to maintain the transducer and the slider next to the data surface of the disk with as low a loading force as possible. The actuator is controlled for positioning the transducer over the correct track according to the data desired on a read operation or to the correct track for placement of the data during a write operation.
In conventional disk drives, the transducer and its slider are formed separately from the suspension and then attached through an operator controlled precision operation. The parts are small and the positioning of each relative to the other must be exact. The transducer must be exactly positioned over the track which in turn means that the suspension must be exactly positioned onto the slider. The suspension must provide flexibility and pitch and roll motion for the slider in the direction of motion of the rotating disk and yet provide resistance to yaw motion. Any error in the placement of the suspension on the slider is detrimental to performance and durability. Even if the suspension and the slider are correctly positioned, the conductor leads to the transducer must then be connected to the transducer. The conductor leads are generally directed along the suspension and connected to an amplifier placed on the suspension or the actuator. The conductor leads must not add to the spring stiffness of the slider while providing good electrical interconnection.
Generally, the conductor leads are bonded by soldering, for instance, to both the transducer output and the amplifier by an operator. Again, errors can cause destruction of the entire combination.
Contact or touching the media by the transducer/slider assembly or head presents unique problems in wear and the possibility of creating a "crash" of the media. To reduce the wear problem and "crash" potential, it has been recognized that the mass of the suspension system must be reduced to minimum. Minimal mass optimizes any physical "impact" the head has upon the media and thereby reduces the possibility of damage and of wear.
To this end there have been disclosed a variety of mechanisms which use a "reed" approach to producing the transducer-suspension. Structured to work in a perpendicular recording environment, the reed device allows the head and suspension to be easily manufactured having: (i) precise throat height control, (ii) precise contact recording transducer placement or the formation of air bearings to achieve specified flying heights, (iii) bonding of sliders to suspensions, and, (iv) easy routing of conductor leads. Some structures, such as described in U.S. Pat. No. 5,041,932 to Hamilton, for example, have included a horizontal transducer with a horizontal first pole piece and a horizontal second pole piece which includes a vertical component that forms the magnetic gap in spaced relationship with the first pole piece.
As noted above, contact recording permits higher signals and greater resolution unregulated by variations in flying height. Unfortunately, the wear associated with contact recording, generally estimated to be 400 microinches over the file life, is usually not acceptable. Another major disadvantage is the fact that formerly this type of head was suitable only for perpendicular recording and was not suitable for longitudinal media. All of this has made the perpendicular recording head of the above design unsuitable for high density recording.